Time schedule controller and parts and housing therefor

ABSTRACT

A time schedule controller wherein the high limit index and the set point index respectively have members movable therewith and alignable in relation to each other only when the set point index reaches the setting of the high limit index. An actuator for terminating the operation of the set point index in the rate of rise thereof is only actuated when the alignable members of the high limit index and the set point index that are operatively associated therewith are in their aligned relation thereof.

United States Patent Hardin 1 July 23,1974

[ TIME SCHEDULE CONTROLLER AND PARTS AND HOUSING THEREFOR [75] Inventor:

[73] Assignee: Robertshaw Controls Company,

Richmond, Va.

[22] Filed: Feb. 20, 1973 [21] Appl. N0.: 333,531

Related US. Application Data [62] Division of Ser. No. 187,641, Oct. 8,1971, Pat. No.

George T. Hardin, Knoxville, Tenn.

[52] US. Cl. 73/431, 116/129 B, 220/30 [51] Int. Cl. G0lp 1/06 [58]Field of Search 73/431, 273; 220/30;

[56] 1 References Cited UNITED STATES PATENTS 1,824,781 9/1931 2,612,1329/1952 Triplett 73/431 X La Bar 73/431 2,862,371 12/1958 Cady 64/42,915,356 12/1959 3,394,594 7/1968 3,430,498 3/1969 Goodwin 73/431Primary ExaminerRichard C. Queisser Assistant Examiner-Daniel M. YasichAttorney, Agent, or Firm-Candor, Candor & Tassone [5 7 1 ABSTRACT A timeschedule controller wherein the high limit index and the set point indexrespectively have members movable therewith and alignable in relation toeach other only when the set point index reaches the setting of the highlimit index. An actuator for termimating the operation of the set pointindex in the rate of rise thereof is only actuated when the alignablemembers of the high limit index and the set point index that areoperatively associated therewith are in their aligned relation thereof.

5 Claims, 15 Drawing Figures TIME SCHEDULE CONTROLLER AND AND HOUSINGTHEREFOR Thisis a division of application, Ser. No. 187,641, A

- filed Oct. 8, 1971, and now U.S..Pat. Ser. No.

wherein each controller is adapted to be set for an initial startingcondition of and for a controlled rate of rise of a set point indexthereof so that a controlled device, such as a heat exchanger, will havethe output effect thereof until the set point index reaches a set highlimit index point at which time the controller will automatically causethe output effect of the controlled device to remain at the high limitthereof for a period of time as set by a hold timer of the controllerfollowed by an automatic shutdown of the operation of the controlleddevice at the end of the predetermined hold period of the controller.Various means have been provided in such time schedule controllers toaccomplish these automatic functions.

I SUMMARY This invention provides an improved time schedule controllerof the above-described type having improved means for controlling'themanual or automatic sequence of operation thereof. J

This invention'also provides an improved time schedule controlled systemas well as improved parts 'for such 2 l Another object of this inventionis to provide an improved time schedule controlled system utilizing sucha time schedule controller or the like.

Another object of this invention is to provide improved parts for such atime schedule controller or the like. v

Other objects, uses and advantages of this invention are apparent from areading of this description, which proceeds with reference to theaccompanying drawings forming a part thereof and wherein DESCRIPTION OFTHE DRAWINGS FIGfl is a front view of the time schedule controller ofthis invention.

of rise of the set point index is adapted to be selected so that thecontroller will tend to maintainan output effect of a controlled deviceat theselected rate of rise of the set point'index until the outputeffect reaches the set condition of the high .limit index, comprisesmeans movable with the high limit index and the set end point index andalignable in relation to each other only when the set point indexreaches the setting ;of the set high limit index. Actuator means areprovided for terminating the operation of the set point index in therate of rise thereof when the actuator means is actuated, the alignablemeans of the high limit index and the set point index being operativelyassociated with the actuator means to actuate the same only when thealignable means are in the aligned relation'thereof. In the embodimentof the time schedule controller of this invention, the alignable meansof the set point index comprises a rotatable cam member movable inunison with t the set point index and-the alignable means of'the highlimit of the set high limit index comprisesan electric tric switch, aswill be apparent hereinafter.

The time schedule controller of this invention also has improved meansfor setting the indexes'thereofinthe desired initial'set positionsthereof. 7

Accordingly, one of theobjects of this invention is to provide animproved time schedulecon-troller having one or more of thenovel'features -.set. forth above or hereinafter shown or described.

FIG. 2 is a view similar to FIG. 1, with the front cover of the timeschedule controller in an open position thereof and with certain partsinside the time schedule controller being broken away.

FIG; 3 is an enlarged, fragmentary view of the bridge and pen assemblyof the controller of FIG. 1.

FIG. 4 is aside view of the bridge and pen assembly of FIG. 3.

FIG. 4A is an enlarged fragmentary cross-sectional "view taken on line99 of FIG. 1 and illustrating the index adjusting means of the timeschedule controller of this invention.

FIG. 10 is a fragmentary, perspective view illustrating the operation ofthe adjustment means of FIG. 9, with the adjustment means being in oneposition thereof.

FIG. 11 is a view similar to FIG. 10 and illustrates the adjustmentmeans being in another position thereof.

FIG. 12 is a fragmentary, cross-sectional view illustrating a solenoidoperated valve means for the control A system of the time schedulecontroller of this invention.

FIG. l3 is a schematic view illustrating the control system that isoperated by the time schedule controller of this invention. 7

FIG. 14 is a schematic view illustrating the electrical circuit for thetime schedule controller of this invention.

DESCRIPTION OF ILLUSTRATED EMBODIMENT While the various features of thisinvention are hereinafter described and illustrated as beingparticularly adapted to control the output temperature effect of a heatexchanger means, it is to be understood. that the various features ofthis invention can be utilized singly or in any combination thereof toprovide a time schedule control for other types of systems as desired.

Also, it is to be understood that the various parts of the time schedulecontroller of this invention can be utilized in other types of controlinstruments or devices, if desired.

Therefore, this invention is not'to be limited to onlythe-embodimentillustratedin the drawings, because wide variety of usesof this invention.

Referring now to FIGS. 1, 2 and 13, the timeschedule controller of thisinvention is generally indicated by the reference numeral and isutilized to control the output temperature effect of a heat exchanger21, FIG. 13, forming part of the controlled system of this inventionthat is generally indicated by the reference numeral 22 in FIG. 13.

The controlled system 22 includes a main steam valve 23 having a valveseat 24 for interconnecting a source of steam 25 to a conduit 26 leadingto the heating coil of the heat exchanger 21, the valve seat 24 beingopened and closed by a valve member 25 being positioned relative to thevalve seat 24 by a pneumatically operated actuator 26 in a manner wellknown in the art whereby an increase of pneumatic pressure in thechamber 27 of the pneumatically operated actuator 26 will cause thevalve member 25 to be moved further away from the valve seat'24 to admitmore steam to the heat exchanger 21 and, conversely, a decrease in thepneumatic pressure in the chamber 27 of the actuator the fluid in thechamber 39 contracts so as to move the 'to the vent opening 31 tends tomaintain the output temperature effect of the heat exchanger 21 at theout- "put temperature effect setting for the process bellows Suchproportional mechanism can be seen inside the casing 41 of thecontroller 20 in FIG. 2 where the cover 42 of the controller 20 has beenmoved to the open position and, in a manner well known in the art, thetemperature setting of the process bellows and- '/or proportionalmechanism 30 is under the control of a set point index link 43 that isadapted to automatically change the temperature setting of theproportional mechanism 30 upon movement of the setpoint index link 43 tochange the output temperature effect of the heat exchanger 21 that isbeing controlled by the proportional mechanism 30 in a mannerhereinafter de the valve member 25 moves farther away from the valvese'at'24 and decreases as' the valve member 25 moves toward the'valveseat 24.

While the particular process being heated by the heat exchanger 21 canvary, the heat exchanger 21 in FIG. 13 is illustrated as heating a dyebath 21' for dyeing textiles and the like.

v As illustrated in FIG. 13, thecontroller 20 for. the system 22includes a balance beam 29 of a proportional mechanism 30 that iswellknown in the art and is therefore schematically illustrated in FIG. 13as having a vent opening device or nozzle 31 for a conduit 32 that isadapted to be supplied fluid pressure from an external source 33- andhas a restrictor 34. therein. The balance beam 29 is positioned relativeto the ventor nozzle opening 31 by a process bellows construction 35 anda feedback bellows-construction 36 respectively interconnected toopposed ends 37 and 38 of the balance beam 29. The process bellows 35has the fluid in the chamber 39 thereof adapted to be expanded andcontracted in relation to the sensing of the output temperature effectof the heatexchanger 21 by the sensing bulb 40 disposed in the processbath 21'. Thus, should the output temperature effect of the heatexchanger 21 exceed the particular output temperature'effect setting ofthe process bellows 35, the resulting expansion of the fluid in thechamber 39 causes the balance beam 29 to. move away from the ventopening 31 a certain amount to vent a greater portion of the fluidpressure in the line 32 than before and, thus, causes a venting of someof the fluid pressure in the chamber 27 of the pneumatic actuator 26 forthe valve means 23 in a manscribed. Also, the'process bellowsconstruction 35 and- /or proportional mechanism 30 is adpated toposition a-process pen link 44 of the controller 20 in relation to theactual output temperature effect of the. heat exchanger 21 as beingsensed by the bulb 40 even though the output temperature of the heatexchanger 21 may be atthat-particular time different than the intended.

setting thereof by the particular position of. the set point index link43.

. In general, the controller 20 of this invention includes a .bridge andpen assembly 45 which has an ink and after the operation of the heatexchanger 21. The

pen and bridge assembly 45 also includes a high limit index or pointer47 which is adapted to be set as a desired high limit temperaturesetting that the output temperature effect of the heat exchanger 21 isto reach by a selector knob 48 on the cover 42 of the casing 41 in amanner hereinafter described so that when the output temperature effectof the heat exchanger 21 reaches the output temperature setting of thehigh limit index 47, the controller 20, in a manner hereinafterdescribed, will hold such output temperature effect for a predeterminedlength of time as set by a hold timer adjustment knob 49 that controlsthe setting of a hold timer motor 50 that is illustrated in FIG. 2 aswell as in the electrical circuit 51 forv the controller 20 in FIG. 14,

The bridge and pen assembly 45 includes a set point index or pointer 52which is adapted to be set at a desired starting output temperatureeffect for a time schedule control of the system 22 by the controller 20by an adjusting knob 53 on the cover 42 of the controller 20 in a mannerhereinafter described, such setting of the set point index 52 settingthe position set point index link 43 -to initially set the proportionalmechanism 30 to tend to maintain the output temperature effect of theheat exchanger 21, when the system 22 is subsequently set intooperation, at the initial output temperature effect setting of the index52.

reached, the same will then be held by the controller for the length oftime set on the hold timer by the knob 49. The rate of rise adjustingknob 54 of the controller 20 sets the rate of rise timer motor 55 of thecircuit 51 at the desired rate of rise setting thereof for thepreviously described purpose.

The cover 42 of the controller 20 includes a manually operated,electrical power on-off switch button 56 which controls a pair ofswitches 57 and 58 in the circuit 51 and respectively disposed in thefused power source lines L and L so that when the button 56 is moved toan on position thereof, the switches 57 and 58 respectively close andinterconnect the fused power source lines L, and L to leads 59 and 60.However, when the button 56 is moved to the off position thereof, thesame opens the switches 57 and 58 to respectively disconnect the powersource lines L and L from the leads 59 and 60.

A start cycle button 61 is provided on the cover 42 of the controller 20and, when pushed to start a particular cycle of operation in the mannerhereinafter described, will cause the hold timer 50 of. the circuit 51to latch the normally closed relay contacts 50 in an open positionthereof while latching the-normally open relay contacts '50 in a closedcondition thereof.

A selector switch 63 and an electro-pneumatic (E/P) valve 64 arecombined in one assembly 65 inside the casing 41 of the controller 20 asillustrated in FIG. 2

with the selector switch 63 being illustrated in the cir-' cuit 51 ofFIG. 14 asbeing movable from the automatic setting positionthereofillustrated in FIG. 14 against a contact 66 to a manual position thereofagainst a contact 67 for a purpose hereinafter described. However, whenthe selector switch 63 is moved to the automatic position illustrated inFIG. 14, an operator can control the system 22 by the controller 20 bymerely setting the high limit index 47 by the knob 48 to the temperatureat which the set point index 52 is to stop at the end of its travel andthe set point index 52 is then positioned to the desired initialtemperature setting by the knob 53. The operator then adjusts thetimer55 by the knob 54 to the desired rate of rise of temperature for thesystem '20 and adjusts the hold timer 50 by the knob 49 to the desiredhold period of the final tempera ture whereby once the power switch 56is in the on position and the start button 61 is actuated, thecontroller 20 will cause the valve 23 to operate the heat exchanger 21in such a manner that once the initial output temperature effect of theheat exchanger 21 reaches the start temperature of the set point index52,

the set point index 52 will be moved by the timer 55 in a mannerhereinafter described at a set rate of rise to cause the heat exchanger21 to have the output temper ature effect thereof rise at a certain rateuntil the output temperature effect reaches the setting of the high 47.When the high limit output temperature effect is i limit index 47 atwhich time the timer motor 50 will systems can be utilized for variouspurposes, such as maintaining a dye bath for textiles and thelike at thedesired rate of rise in temperature and then at the desired holdtemperature thereof for a pre-selected time period.

While one of the features of this invention is to provide improved meansfor the controller 20 to cause the controller 20 to perform theaforementioned time schedule control of the system 22 and such means isprovided by the pen and bridge assembly 45 later to be described, it isbelieved necessary to further describe the system 22 and the circuit 51in order to fully understand the operation of the controller 20 whenutilizing the various features of this invention.

Accordingly, as illustrated in FIG. 13, the system 22 has the portionthereof disposed within the dash-dotted rectangle 68 physically disposedwithin the casing 41 of the controller 20 wherein the conduit 32 forthesupply pressure 33 has a branch conduit 69 leading therefrom in advanceof the restrictor 34 for supplying supply pressure to a conventionalamplifying pneumatic relay 70.

The amplifying pneumatic relay 70 is adapted to direct its outputpressure into a conduit 71 with such output pressure being proportionalto but an amplification of the signal pressure being received therebyfrom a conduit 72 interconnected to the conduit 32 downstream from therestrictor 34. Thus, the relay 70 senses and amplifies the pressure inthe line 32 downstream from the restrictor 34 which pressure is inrelation to the amount of'opening or closing of the vent nozzle 31 bythe balance beam 29 so that such output pressure in line 71 and beingdirected by the conduit 73 not only to the chamber 27 of the pneumaticactuator 26 for the main steam valve 23, but also to the chamber 74 ofthe feedback bellows 36 is in relation to the amount of opening orclosing of the nozzle 31 by the balance beam 29. Thus, a movement of thebeam 29 away from the nozzle 31 by the process bellows 35 sensing atemperature effect of the bath greater than the particular setting ofthe set point index line 43 causes a corresponding drop in pressure inthe conduit 32 downstream from the restrictor 34 so that the amplifier70 has its output pressure 71 correspondingly decreased whereby thevalve member 25 moves closer to the valve seat 24 to decrease the outputtemperature effect of the heat exchanger 21. However, since the pressurein the chamber 74 of the feedback bellows 36 correspondingly decreases,the same tends to move the beam 29 back toward the nozzle 31 to therebyincrease the pressure in the line 32 and, thus, to the relay 70 to causean increase in the output pressure -71 thereof to tend to open the valvemember 25 away from the valve seat 24 whereby the feedback arrangement36 tends to eliminate an overshooting of the control of the heatexchange 21 in a manner well known in the art. Thus, it is sufiicient tostate that the controller 20 for the sys tem 22 is adapted to maintainthe output temperature effect of the heat exchanger 21 at the starttemperature setting of the set point index 52 and maintain such outputtemperature effect at a rate of rise that the index 52 is being moved bythe rate of rise timer 55 in a manner hereinafter described because theposition of the set point link 43 determines the temperature setting forthe proportional mechanism 30 at any one time in the operation of thesystem 22 by the controller 20.

The conduit 32 downstream from the restrictor 34 of the system 22 isinterconnected by a conduit 75 to a vent nozzle 76 that is opened andclosed by a valve member 77 carried on a flapper armature 78 of the E/Pvalve 64. The armature 78 is normally urged to an open position by aspring means 79 in FIG. 13 and an electrical coil 80, when energized, isadapted to attract and pull the armature 78 downwardly in opposition tothe force of the spring 79and have the valve member 77 close the ventopening 76 as long as the coil 80 is energized. However, when the coil80 is de-energized, the spring means 79 moves the valve' member 77 awayfrom the vent opening 76 to open the conduit 32 so that no pressurebuild-up can occur in the line 32 and, thus, in the output line 71 ofthe relay 70 so that the main steam valve 23 will automatically close bythe force of the spring 28 whenever the vent nozzle 76 isin an openposition. Thus, it requires the energizing of the coil 80 to close thevent nozzle 76 in order to permit the main steam valve 23 to be operatedby the controller 20 in the manner previously described.

The E/P valve 64, while illustrated. schematically in' FIG. 13, isillustrated in detail in FIG. 12 and it can be seen that the vent nozzle76 thereof comprises a tubular member 81 passing through the center ofthe electrical coil 80 and the armature of flapper 78 when moved to theopen.position by the spring 79 abuts against a stop arm 82 of anL-shaped frame member 83 that has one leg 84 thereof interconnected tothe tension spring 79 with the other end of the tension spring 79 beinginterconnected to the armature 78. Thus, when the coil 80 is energized,the armature 78 is pulled downwardly to close the upper 'endof the tube81 and permit a pressure buildup in the line 75 and, thus, in the maincontrol line 32 for the reasons previously set forth.

As illustrated in FIG. 14, the coil 80 for the E/P valve 64 is adaptedto have one side 81 thereof interconnected by a lead 82 to the selectorswitch 63 and the the lead 60 of the circuit 51.

A chart drive motor 85 is adapted to have one side selector switch 63 isinterconnected by a lead 96'to' the lead 94 intermediate the main lead59 and relay contacts-50. The contact 66 for the selector switch 63 isinterconnected to the lead 59 by a lead 97. v

A hold light 98 has one side 99 thereof interconnected to the lead 60 bya lead 100 while the other side 86 thereof interconnected to the powersource lead L by a lead 87 and the other'side 88 thereof interconnectedby a lead 89 to the power source lead L so that whenever the controller20 is plugged into a power source, such as a conventional 110 voltalternating current source, the chart 46 of the controller 20 is drivenby the chart drive motor 85 at a continuous rate so that the ink pen 46continuously records thereon the actual sensed output temperature effectof the process bath 21 even though'the controller 20 is not operatingthe heat exchanger 21 and the main steam valve .23 is disposed in itsclosed position. A pilot light 9.0 is placed end of cycle light 93 isplaced across the leads 59 and pose hereinafter described and thecontact 67 for the across the leads 5960 by leads 91 and 92. Similarly,an t 101 thereof is interconnected bya lead 102 to a normally opencontact 103 of a limit switch 104 which forms part of the pen and bridgeassembly 45 later to be described.

A switch blade 105 of the switch 104' is interconnected to the lead 59and normally is disposed against a contact 106 to electricallyinterconnect the lead 59 to a lead 107 that is interconnected to acontact 108 of a pneumatically operated switch 109. The switch 109 hasits switch arm 110 normally bridging the contact.

108 with a contact 111 as long as the pneumatic sensor 112 thereofsenses that the output pressure from the relay 70 to the pneumaticallyoperated valve 23 does not exceed a full open pressure which in thesystem. 22 is a pressure above '15 psi. Since the control range for theoutput pressure from the relay 70 to the steam valve 23 is normally 3 to15 psi, the switch 109 is normally disposed in its closed positionbridging the contacts 108 and 111 unless the same senses a pressureabovel psi. r The contact 111 is interconnected by a lead 113 to oneside 114 of a rate of rise light 115 while the other 119 thereofinterconnected by a lead 120 to the lead 60 and the other side 121thereof interconnected by a lead 122' to normally open relay contacts 55of the rate of rise timer motor 55. The rate of rise timer motor 55opens and closes the contacts 55' on a percentage of time basis duringthe running of the rate of rise timer motor 55 so that the closingpercentage of the contacts 55 may be varied by the setting of the rateof rise adjustment knob 54 on the controller 20 whereby the timer 55will operate-the drive motor 118 in an on and off manner to move the setpoint index 52 at the desired rate of rise thereof as will be apparenthereinafter.

The rate of rise timer motor 55 has one side 123 thereof interconnectedto the lead 60 by a lead 124 while the other side 125 thereof isinterconnected to the lead 113 by a lead 126 that is also connected toone side of the normally open relay contacts 55 of the timer motor 55.The hold timer motor 50 has one side 127 interconnected by'a lead 128 tothe lead 60 while the other side 129 thereof is interconnected by a lead130 to the lead 102,-.

As illustrated in FIGS. 3-8, the bridge and pen assembly 45 includes apair of bridge members or frame plates 131 and 132 for'mounting thebridge and pen assembly 45 in the controller casing 41, the upper bridgemember 131 being supported on the lower bridge member 132 by a pluralityof posts 133. A cylindrical pin 134 is carried by the bridge plates 132and 131 and does not rotate relative thereto-as the same is held inplace by set screws such as at 135, FIG. 4A. A bushing 136 is carried bythe upper bridge member 131 and has the pin 134 passing therethroughbeyond the .top beveled surface 137 thereof.

The pen 46, the high limit index 47 and the set point index 52respectively have U-shaped parts 138, 139

V and 140 with the upper arms 141, 142 and 143 thereof provided withopenings 144, 145 and 146 passing therethrough andreceiving the portionof the pin 134 that projects beyond the bushing 136, as illustrated inFIG. 4A. Spacers. 147 and 148 are respectively disposed on oppositesides of the intermediate arm 142 of the high limit index 47. The arms141-143 are held in the stacked relation illustrated in FIGS. 4 and 4Aby a retaining ring 149 and the pin 134 isadjusted such that a gap ofapproximately 0.010 of an inch exists between the pen arm 141 and theretaining ring 149 when all of the leverage members 141-143 are in thedownward position, as illustrated in FIG. 4, whereby sufficient end playis provided to prevent any possibility of binding of the leveragemembers 141-143 in their rotation on the pin 134.

The U-shaped member 138 for the pen 46 has the lower arm 150 thereofprovided with an opening 151 passing therethrough and receiving the pin134 intermediate the bridge members 131 and 132, as illustrated in FIG.7. A link 152 also has an opening 153 passing therethrough andreceivingthe pin 134 with the link 152 being fastened to the arm 1500f the penassembly 46 so that movement of the link 152 by the interconnectedprocess pen, link 44 willcause the pen 46 to pivot or rotate on the pin134 and mark across the chart 46 as the'chart 46 is being driven by itsdrive motor 85. The lower legs 154 and 155 of the U-members 139 and 1 40for the indexes 47 and 52 respectively receive the pin 134 throughsuitable openings therein with such of FIG. 14, the geared down outputshaft 174 thereof rotates the shaft 171 and, thus, the pinion gear 169to drive the cam-gear 157 about the pin 134 and, thus, rotate the index52 about the pin 134 in unison therewith.

The arm 154 of the U member 139 for the high limit index 47 extendsbeyond the cam gear member 156 thereof and carries the limit switch 104in fixed position thereon, the limit switch 104 having an operatingplunger 105 which when in its out condition makes contact with thecontact 106 of the circuit 51 and when caused to move inwardly by a camfollower 175 thereof being forced out of a recessed cam part 176 of theouter periphery 161' of the cam gear member 156, as illustrated in FIG.5, causes the switch blade 105 of FIG. 14 to be moved out of contactwith the contact 106 and placed into contact with the contact 103 forarms 154 and 155 respectively being riveted as illus- As illustrated inFIG. 5, the cam-gear member 156 for the high limit index 47 has a part160 of the outer periphery 161 thereof formed with gear teeth thereonwhich are adapted to be disposed in meshing engagement with a piniongear 161 fastened by a set screw 162, FIG. 8, to a shaft member 163rotatably carried by the bridge members 131 and 132 and having anextension 164 passing through the upper bridge member 131 and beingfastened by a set screw 165 to a knob member 166 adapted to rotate-theshaft 163 in a manner hereinafter set forth.

Similarly, the cam-gear member 157 for the index 52 has a portion 167 ofthe outer periphery 168 thereof provided with gear teeth disposed inmeshing relation with the gear teeth of apinion gear 169 fastened by a apurpose hereinafter described.

The cam follower arrangement 175 is so constructed and arranged that thesame does not ride on the outer periphery 161' of the camgear member156for the high limit index 47 but is movable into the recessed cam area176 thereof. However, the cam follower 175 does ride in the elongatedcam portion 177 of the gear member 157 when the same is rotatingrelative thereto.

, The cam wheels or members 156 and 157 are so constructed and arrangedthat the cam follower 175' of the cam assembly 175 will be midwaybetween the highest and lowest level of its cammed position as it ridesout of the recess 177 of the member 157 toward the outer peripherythereof when the indexes 47 and 52 are at their point of coincidence sothat the snap acting switch 104 can be made to trip at the exact pointof coassemblies 47 and 52 to force the cam follower out of the cam 176of the gear cam 156 for the high limit index 47 and tend to ride on thehigh portion of the outer periphery 161 of the rear cam'157 of the setpoint index 52. 7

Therefore, it can be seen that when the high limit index 47 has been setto adesired position thereof by the rotation of the pinion gear 161rotating the'cam gear member 156 and, thus, the high limit index 47, theswitch 104 is being positioned therewith so that the set point index 52when driven by the motor 118 into a position of coincidence with thehigh limit index 47 will have its cam 157 operate the snap switch 104 tomove the contact from the contact 106 to the contact 103 for a'purposehereinafter described to start the hold time of the control circuit 51.

As previously stated, movement of the set point index 52 by the motor118 causes the set point link 43 that is interconnected to the set pointindex 7 to adjustv the proportional mechanism 30 to cause the outputtemperature effect-of the heat exchanger 21 to follow the new setting ofthe index 52 as the same is being driven toward the high limit settingof the index 47 at which point the indexes 52 and 47 will be incoincidence so that the cam-gear 157 can operate the limit switch 104from the position illustrated in FIG. 14 to open the r 11 contact 106and close the contact 103 for a purpose hereinafter described. x 1

In order to initially adjust the positions of the shafts 163 and 171 torespectively set the high inlet position for theindex 47 and thestarting position for the set point index 52, the adjustment knobs 48and 53 on the cover 42of the controller casing 41 are formed in alikemanner to respectively control the inside knobs 166 and 172 onthe shafts163 and 171.

Since such structureiis identical, only one such structure isillustrated in FIGS. 9-11 and, since the same comprises the adjustingknob 48 for the high limit index 47, it is to be understood that likestructure is provided for the knob 53 to adjust the initialposition ofthe set point index 52.

As illustrated in FIG. 9, the cover 42 has a sleeve 178 passingtherethrough and receiving a cylin'dricalportion 179 of a rectangularlycross sectioned rod 180 that has the non-cylindrical portion thereofextending.

below the sleeve 178 and passing through a rectangular opening 181 in aplate 182 having a pair of outwardly directed, diametrically disposedtangs 18 3 adapted to respectively be received in diametrically opposednotches 184 formed through the knob 166 for the shaft 163 while theremainder of the plate 182 is received in a central recess 185 .in theknob 166, as illustrated in FIG. 9. The plate 182 is held on the rod 180bya threaded fastening member 186 and is urged against the head 187 ofthe threaded fastening member 186 by a compression spring 188 disposedbetween the sleeve 178 and the plate 182, as illustrated in FIG. 9,whereby the plate 182 is adapted to move up and down on the rod 180" inopposition to the force of the compression spring 188.

As illustrated in FIG. 9, the adjustment knob 48 is fastened to thecylindrical portion 179 of the rod 180 by a set screw 189 so that theknob 48 will rotate in unison with the rod 180.

the tangs 183 merely engage against the upper surface 191, asillustrated in FIG; 10, permitting the plate-.182

. to telescope on the rod 180 in opposition to the force of thecompression spring 188 in order to permit the cover 42 to move to itsfully closed position. Thereafter, the operator merely rotates theparticular knob 48 or 53 at least a quarter of a turn in any directionand the tangs 183 of the plate 182 will snap intothe slots 184 under theforce of the compression spring 188 in the manner illustrated in FIG. 11as the same come into alignment with the notches 184 so that theintercon nection between the outer knob 48 or 53 on the cover 42 to therespective inner knob 166 or 172 is a simple operation merely thereafterrequiring rotation of the knobs 48 and 53 lock the tangs 183 in place.Thereafter, the knobs 48 and 53 will respectively adjust the indexes 47and 52 in the manner previously described to set the same at the desiredbeginning positions thereof for a controlled operation for the system 22as now to be described.

When the operator presses the power button 56 for the controller to movethe same to an on position thereof, the switches 57 and 58 are moved'totheir closed positions to interconnect the fused power source 7 lines Land L to the leads 59 and 60 whereby the pilot light 90 is now turned onas the same is placed across the power source leads L and L If theselector switch 63 is in its manual position so as to be away from thecontact 66 and against the contact 67, the coil 80 of the E/P valve 64will be. energized to close the valve member 77 against the vent nozzleopening 76 of the tubular member '81 whereby output pressure is providedfrom the relay 70 to the conduit 73 for controlling the main steam valve23.

However, if an automatic operation for the controller 20 is provided,the selector switch 63 is disposed in the automatic position illustratedin FIG. 1 whereby the switch 63 is closing against the contact 66 sothat current cannot be'directed to the solenoid until the normallyopened relay contact 50" are closed. Since the contacts 50" are in theopen position when the hold timer motor 50 is not timing and thecontacts 50' thereof are in the closed position, as illustrated in FIG.14, as is true before the beginning of each process run, the end cyclelight 93 will be initially on as the same is energized through normallyclosed contacts 50'.

The operator then sets the high limit index 47 through the knob 48 tothe desired temperature at which the set point index 52 is to stop atits end of travel. The set point index 52 is then positioned by the knob53to the desired initial temperature setting that the controller 20 isto control the heat exchanger 21.

. Thus, the limit switch 104 is moved to a certain position when thehigh limit index 47 is so moved to a set position and the cam gear 157for the set point index 52- is moved to a certain beginning positionthereof so that the cam follower 175' is in its outermost positionwhereby the limit switch 104has its blade 105 against the contact-106,as illustrated in FIG. 14.

The operator then adjusts the rate of rise adjustment knob 54 to thedesired rate of rise temperature that the set point index 52 is tocontrol the heat exchange 21 in reaching the high limit temperaturesetting of the high I limit index 47. The operator then sets the holdtimer knob 49 to the desired length of time that the high limittemperature for the heat exchanger 21 is to be maintained by thecontroller 20.

After all of the aforementioned selections have been made, the operatorthen depresses the start button 61 which acts on the hold timer 50 tolatch the contacts 50' in an open position thereof and the contacts 50"thereof in a closed position thereof whereby the end of cycle light 93now goes out.

If the selector switch 63 is in the auto position illustrated in FIG.14, the coil'80 of the E/P valve 64 will now be energized since thecontacts 50 are closed allowing the steam valve 23 to open to begin toheat the desired process material by the heat exchanger 21. As

long as the pressure operated switch 109 is closed, electrical currentis applied to the rate of rise timer motor 55, rate of rise light andset pointdrive motor 118. However, the running time of set point drivemotor 118 is regulated by the closing interval of the contacts 55 whichis a function of the percentage of the operation of the timer 55 wherebythe average rate at which the set point index 52 is driven by the timermotor 118 up scale by the motor 118 toward the hih limit index 47 isdetermined by the setting of the knob 54 for the rate of rise selection.

If the pneumatically operated switch 109 should I open, the rate of risetimer 55 and set point drive motor control range of output pressure forthe controller is normally 3 to 15 psi. On the reverse acting steamvalve 23, the output pressure increases in the chamber 27 when more heatis demanded and most steam valves are wide open at pressure'sexceeding15 psi. When the process is incapable of rising at the rate of movementof the set point index 52, the output pressure will exceed 15 psi andwill cause the pressure operated switch 109 to open. By appropriatechoice of proportional band setting and/or pressure switch setting, theactual permissible process lag may be varied according to need.

The rise of the set point index 52 by the timer motor 118 will continuein the manner previously described to cause the output temperatureeffect of the heat exchanger 21 to continuously increase until theswitch 104 is tripped by the alignable members 157 and 156 for theindexes 52 and 47 being coincident as previously described so that theblade 105 of the switch 104 now moves away from the contact 106 and isplaced against the contact 103. Such position of the switch 104completely disconnects the set point drive motor 118 and timer 55 fromacross the power source L and L to terminate further up scale movementof the set point index 52 and, thus, increase of output temperatureeffect of the heat exchanger 21.

At this time, the power source 61 and 62 is now applied to the holdlight 98 and to the hold timer motor 50 whereby the timer motor 50 willcontinue to run for the time period as set by the knob 49 so thattheoutput temperature effect of the heat exchanger 21 is maintainedat'the high limit temperature setting of the high limit index 47 forthis timed period as the set point index 52 is now stationary at thishigh temperature setting so as to maintain the controller at the hightemperature setting through the now stationary link 43 thereof.

When the hold timer 50 runs down, the hold timer contacts 50' and 50 arereversed so that the contacts 50 now close and the contacts 50" openwhereby the However, if the selector switch 63 was in a manual positionso that the same was against the contact 67 rather than against thecontact 66, the coil 80 for the El? valve will remain energized eventhough the timer motor is turned off and the process will not shut downwhereby shut down must then be affected by the use of the power switch56 being turned to the off" position at the discretion of the operator.

Therefore, it can be seen that a unique means is provided for providingan automatic cycle of operation of the controller 20 to control thesystem 22 in such a manner that the rise of the set pointindex 52 froman initial setting thereof to a high temperature setting coincident withthe setting of the high limit index 47 will cause the heat exchanger 21to be held at such high limit output temperature effect for a timedperiod so that when the timed period has elapsed, an automatic shut downof the process will be completed. Also, it can be seen that improvedparts for such a time schedule controller have been provided.

While the form of the inventionnow preferred has been disclosed asrequired by the patent statutes, other forms may be utilized all comingwithin the scope of the appended claims.

What is claimed is:

1. ln an instrument for measuring a condition and having a casing anddoor means for pivotally opening and closing said casing, said doormeans having an adjusting member thereon and said casing having thecondition adjustable member therein for being adjusted by said adjustingmember when said door means is closed, the improvement wherein saidadjusting member has outwardly directed tangs and said adjustable memberhas slots therein for receiving said tangs when said tangs are alignedtherewith and said door means is closed whereby said adjusting memberand said adjustable member are coupled together for rotation in unisonrelative to said instrument.

2. In an instrument as set forth in claim 1, the further improvementwherein said tangs of said adjusting member are axially movable thereon.

3. In an instrument as set forth in claim 2, the further improvementwherein said tangs are biased to one position relative to said adjustingmember by a compression end of cycle light 93 is turned on, the holdlight 98' goes the controller output pressure falls to zero through themovement of the valve member 77 away from the'valve nozzle 76 of the El?valve 64 and the heat exchanger 21 will now return the process to a shutdown condition thereof.

are keyed together so that said body member is axially movable relativethereto while rotatable in unison therewith.

1. In an instrument for measuring a condition and having a casing and door means for pivotally opening and closing said casing, said door means having an adjusting member thereon and said casing having the condition adjustable member therein for being adjusted by said adjusting member when said door means is closed, the improvement wherein said adjusting member has outwardly directed tangs and said adjustable member has slots therein for receiving said tangs when said tangs are aligned therewith and said door means is closed whereby said adjusting member and said adjustable member are coupled together for rotation in unison relative to said instrument.
 2. In an instrument as set forth in claim 1, the further improvement wherein said tangs of said adjusting member are axially movable thereon.
 3. In an instrument as set forth in claim 2, the further improvement wherein said tangs are biased to one position relative to said adjusting member by a compression spring.
 4. In an instrument as set forth in claim 3, the further improvement wherein said adjusting member includes a shaft, said tangs having a body member telescopically disposed on said shaft.
 5. In an instrument as set forth in claim 4, the further improvement wherein said body member and said shaft are keyed together so that said body member is axially movable relative thereto while rotatable in unison therewith. 